Bhagavad Gita, Chapter 11, Verse 54

But by the single-minded devotion I may in this Form, be known, O Arjuna, and seen in reality, and also entered into, O scorcher of foes.

The real answer to how any of this becomes possible finally gets named here, plainly, devotion, nothing else.

After several verses naming what doesn't work, Krishna states directly what does. Real, undivided devotion is offered as the one genuine path to actually knowing him.